Open access is a convergence of the belief by scholars that distributing their scholarly works as widely as possible is in the best interest for their research and the public good, with the invention of the Internet and World Wide Web that potentially allows worldwide access.
OA is a step to bridging the knowledge and digital divide.
Open access publishing is about equitable access and greater accessibility around the globe not just for the privileged who can afford to subscribe to a journal or pay for a research article or book. It challenges the practices of institutions buying back publications their own authors have written, of limiting the use of research results supported by public funds, and of publishers holding copyright to author's works such that authors must seek permission to reuse all or part of their own content. OA opposes inflated publisher pricing such that library budgets can no longer afford to subscribe to content that their own scholars produce.
Open access research outputs are not free to produce, publish, disseminate, or preserve since all have costs associated with them. Nor does open access mean universal access, as there are language, technological and censorship barriers to overcome in many parts of the world.
OA is a step to creating a more sustainable scholarly communication ecosystem that encourages openness and sharing of all facets of scholarly and research outputs, and that minimizes the barriers caused by prohibitive pricing for library subscriptions and other electronic content.
Open Access to Scholarly and Scientific Research Articles (SPARC (the Scholarly Publishing and Academic Resources Coalition) "to enable the open sharing of research outputs and educational materials in order to democratize access to knowledge and accelerate discovery..."
Open Access (detailed overview of terms and history) includes Gold OA (publish in an open access journal) vs. Green OA (self-archiving), Gratis OA (free of charge) and libre OA (free of charge plus additional re-use rights), and more.
The Budapest Open Access Initiative (BOAI/February 2002), Bethesda Statement on Open Access Publishing (June 2003), and the Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities (October 2003) focused the OA movement at a critical juncture. BOAI is often called the catalyst for bringing independent small movements around the globe together as one community and putting a name to the movement.